Features and Benefits
- High Efficiency: Up to 96%
- 5A Output Current
- 4V to 20V VIN Range
- Integrated Power N-Channel MOSFETs (70mΩ Top and 35mΩ Bottom)
- Adjustable Frequency 800kHz to 4MHz
- PolyPhase® Operation (Up to 12 Phases)
- Output Tracking
- 0.6V ±1% Reference Accuracy
- Current Mode Operation for Excellent Line and Load Transient Response
- Shutdown Mode Draws Less Than 15μA Supply Current
- LTC3605: 15V Absolute Maximum VIN
- LTC3605A: 22V Absolute Maximum VIN
- The LTC3605A Is Pin Compatible with the LTC3605
- Available in 24-Pin (4mm × 4mm) QFN Package
The LTC3605A is a high efficiency, monolithic synchronous buck regulator using a phase lockable controlled on-time constant frequency, current mode architecture. PolyPhase operation allows multiple LTC3605A regulators to run out of phase while using minimal input and output capacitance. The operating supply voltage range is from 20V down to 4V, making it suitable for dual, triple or quadruple lithium-ion battery inputs as well as point of load power supply applications from a 12V or 5V rail.
The operating frequency is programmable from 800kHz to 4MHz with an external resistor. The high frequency capability allows the use of small surface mount inductors. For switching noise sensitive applications, it can be externally synchronized from 800kHz to 4MHz. The PHMODE pin allows user control of the phase of the outgoing clock signal. The unique constant frequency/controlled on-time architecture is ideal for high step-down ratio applications that are operating at high frequency while demanding fast transient response. Two internal phase-lock loops synchronize the internal oscillator to the external clock and also servos the regulator on-time to lock on to either the internal clock or the external clock if it’s present.
|Input Voltage Range|
|LTC3605||4V to 15V|
|LTC3605A||4V to 20V|
- Point of Load Power Supply
- Portable Instruments
- Distributed Power Systems
- Battery-Powered Equipment
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Demonstration circuit 1897 is a step-down converter, using the LTC3605A monolithic synchronous buck regulator. The DC1897B has a maximum input voltage of 20V, and is capable of delivering up to 5A of output current at a minimum input voltage of 4V. The output voltage of the DC1897B can be set as low as 0.6V, the reference voltage of the LTC3605A. It has a jumper that allows the output to be set at 2.5V, 3.3V or 5V. The LTC3605A has a phase-lock-loop circuit, allowing high current multiphase operation of several DC1897Bs in parallel.
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.
Models for the following parts are available in LTspice:
LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.
To open the project file for this circuit:
Step 1: Download and install LTpowerCAD on your computer.
Step 2: Click on the link(s) in the section below to download part-specific project files.
Step 3: If the project file doesn't run, right-click the link and select "Save Target As." Then start the LTpowerCAD tool and open the project file by selecing "Open Project" from the "File" menu.
LTpowerCAD Project Files
Design tools for the following parts are available in LTpowerCAD:
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.